Direct access storage devices (DASD), commonly known as hard drives or hard disk drives (HDDs), have become part of every day life, and as such, expectations and demands continually increase for greater speed for manipulating data and for holding larger amounts of data.
Operating temperatures can limit the performance of an HDD, and if not compensated for in some manner can render an HDD inoperable. In particular, cold operating temperatures increase the coercive force of the magnetic medium and thus the magnetic field needed in order for the write head to write data to the magnetic medium. Cold enough temperatures often cause this coercive force to increase beyond the capabilities of the write head of the HDD. An example of such a cold operating temperature is an HDD in an extreme temperature environment of −30° C. Though cold temperatures are extreme, they may commonly be experienced on cold winter days, such as, for example, within an HDD installed in an automobile navigation system. At cold operating temperatures, it is often required to heat the magnetic medium to a higher temperature so that the magnetic field required of the write head for writing data is reduced to a level which the write head of the HDD can produce.
In other instances, a room temperature magnetic medium may be purposely chosen with a high coercive force, as a design choice, so that a high magnetic field is required to change the magnetization of the magnetic medium storing the data. Such a design allows for higher areal density and more magnetically stable storage of data. However, such a design may offer similar problems experienced with a cold medium. For example, even at room temperature, the magnetic field required of the write head for writing data to the magnetic medium may, by design, be higher than the write head of an HDD is able to produce. As with cold temperatures, heating the magnetic medium to a higher temperature is a strategy by which the coercivity of the magnetic medium may be lowered in order to reduce the magnetic field required of the write head for writing data to a level which the write head of the HDD can produce.
Various methods and systems for heating magnetic media are known or theorized, with most being complex, inefficient, difficult, and/or expensive to implement. An example of an often recited method is the use of a laser to direct energy onto a track or region of a disk in order to heat the medium just prior to the writing of data. While this method is functional, it is complicated and relatively expensive to implement such laser heating in an HDD. Moreover, lasers are typically inefficient, and thus consume a large amount of power in order to perform such heating. Such power consumption is not desirable in many environments, such as, for example, in mobile devices which operate on battery power. Another method for heating magnetic medium of an HDD is simply heating the entire HDD, however, this is not energy efficient and is generally slow (possibly taking a minute or longer), thus delaying a user's use of the HDD.